The present invention relates to embodiments of a transmitting device with an antenna, such as used in tire pressure sensing and other wireless vehicle sensing systems. Conventional tire pressure sensors are installed within tires of the vehicle or on a valve stem and include radio frequency (RF) transmitters. The sensors transmit periodic signals indicating tire conditions (e.g., pressure, temperature, etc.) of the respective tires of the vehicle. Receiving antennas placed at multiple locations throughout the vehicle receive the tire condition signals from the various transmitters.
A tire pressure monitoring system, such as used on a commercial vehicle, may include multiple receiving antennas since the tire pressure sensors may be separated by large distances from each other. Signals from tire pressure sensors located within the pressurized tire may suffer from attenuation as the signal passes through the tire sidewalls. The antenna may also be detuned based on its proximity to the edge of a rim inside a steel belted tire. In addition, the attenuation of the signal affects the number of receiving antennas required on the vehicle. There is a need for an improved transmitting device to address these issues.